Henry Eyring

Transition state theory, developed by Henry Eyring in 1935, provides a quantitative framework for calculating the rates of chemical reactions based on the properties of the activated complex—the unstable transition state through which reactants must pass to become products. The theory connects molecular-level energy surfaces to macroscopic reaction rate constants.

The Eyring equation relates the rate constant of a chemical reaction to temperature, the Boltzmann constant, Planck's constant, and the Gibbs free energy of activation. Unlike the empirical Arrhenius equation, the Eyring equation has a theoretical basis in statistical mechanics and is widely used to analyze the temperature dependence of reaction rates.

Eyring spent most of his career at the University of Utah in Salt Lake City, where he joined the faculty in 1946 and remained active for decades. Prior to Utah, he held positions at the University of Wisconsin and Princeton University, where he developed the transition state theory.

Despite the enormous influence of transition state theory on physical chemistry, Eyring never received a Nobel Prize. His contribution is often cited as one of the most significant theoretical advances in chemical kinetics of the 20th century, and many in the field consider his omission a notable one.